The present invention relates to a printing material set for preparing bar-code labels by the pressure-sensitive printing method, by which the bar-code labels utilized in the statistical treatment of the data concerning the distribution of commodities such as the names, prices, weights, etc. of commodities are simply prepared and utilized.
The bar-code labels have hitherto been prepared by the transcription to sheets of ordinary paper while using an ink, and in addition to this method, a method has been devised by which printing is effected by using the simplified printers respectively fitted to the carbon paper, heat-sensitive paper or magnetic tape.
However, according to the above-mentioned printing system, for instance, in the method using an ink, the hands of the operator of the printer are apt to be stained in the case of exchanging the ink-roller, printed images are apt to be uneven and a special means are necessary for stabilizing the thus printed image against friction. In the method of using heat-sensitive paper, because of the co-existence of the colour-developer and the colour-coupler on the uppersurface of the label even after the printing, stains are apt to be caused by colouring due to post-heating of the material. In the case of using carbon paper, the transcribed pigment and wax have adhered onto the surface of the label and accordingly, the clearness of the image is deteriorated by heat and/or friction.
The above-mentioned defects are the cause of reducing the accuracy of reading the printed images, and such a reduction of the accuracy of reading has been experienced remarkably in the cases of printing the bar-codes on occasion and of attaching the printed labels onto the articles on occasion.
The object of the present invention is to provide a novel printing material set for preparing bar-code labels which has overcome the defects of the bar-code labels prepared by the conventional methods.
As a result of the present inventors' studying in order to solve the defects of the conventional bar-code labels, the present inventors have found that by using microcapsules containing minute particles of pigment dispersed in a solution of an adhesive component dissolved in an organic solvent, while without using a colour-developer, the reduction of the accuracy of reading the printed images of the bar-code label is improved, and the present invention has been attained on the basis of the above-mentioned finding.